On Sep 29, 2011, at 10:10 AM, maxbre wrote:
hello all,
this is my reproducible example data frame
test<-structure(list(date = structure(c(1262300400, 1262304000,
1262304000,
1262307600, 1262307600, 1262311200, 1262311200, 1262314800,
1262314800,
1262318400, 1262318400, 1262322000, 1262322000, 1262325600,
1262325600,
1262329200, 1262329200, 1262332800, 1262332800, 1262336400,
1262336400,
1262340000, 1262340000, 1262343600, 1262343600, 1262347200,
1262347200,
1262350800, 1262350800, 1262354400, 1262354400, 1262358000,
1262358000,
1262361600, 1262361600, 1262365200, 1262365200, 1262368800,
1262368800,
1262372400, 1262372400, 1262376000, 1262376000, 1262379600,
1262379600,
1262383200, 1262383200, 1262386800), class = c("POSIXct", "POSIXt"
), tzone = "")), .Names = "date", row.names = c(NA, -48L), class =
"data.frame")
given that, my objective is to create a new variable accounting for
the
julian day (i.e. the number of consecutive days elapsed from a fixed
origin
date)
and these are (among many others) my (most) unsuccessful attempts…
library(chron)
#not working!
test$jday<-julian(test$date, origin=as.POSIXct(test$date))
I thought the error message was reasonably informative:
Error in julian.POSIXt(test$date, origin = as.POSIXct(test$date)) :
'origin' must be of length one
And the obvious fix was to just give it one starting date:
> test$jday<-julian(test$date, origin=as.POSIXct(test$date)[1])
> test$jday
Time differences in days
[1] 0.00000000 0.04166667 0.04166667 0.08333333 0.08333333
0.12500000 0.12500000 0.16666667 0.16666667 0.20833333
[11] 0.20833333 0.25000000 0.25000000 0.29166667 0.29166667 0.33333333
0.33333333 0.37500000 0.37500000 0.41666667
[21] 0.41666667 0.45833333 0.45833333 0.50000000 0.50000000 0.54166667
0.54166667 0.58333333 0.58333333 0.62500000
[31] 0.62500000 0.66666667 0.66666667 0.70833333 0.70833333 0.75000000
0.75000000 0.79166667 0.79166667 0.83333333
[41] 0.83333333 0.87500000 0.87500000 0.91666667 0.91666667 0.95833333
0.95833333 1.00000000
attr(,"tzone")
[1] ""
attr(,"origin")
[1] "2009-12-31 18:00:00 EST"
#not working!
test$jday<-julian(test$date, origin=test$date)
#not working!
test$jday <-julian(as.Date(test$date, "%m"),
as.Date(test$date, "%d"),
as.Date(test$date, "%Y"),
origin=c(month=1, day=0, year=2010))
Exactly the same errors.
any help for this?
Yes:
Read the error messages for meaning and include them in your postings.
--
David Winsemius, MD
West Hartford, CT
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